1. Field of the Invention
The present invention relates to a safe antenna, and particularly to a safe sticker antenna for mobile phones.
2. Description of the Related Art
Mobile phone makers currently adopt a helical coil antenna to constitute a mobile phone. Because the antenna sticks out the housing of the mobile phone, it is not only easily broken down and inconvenient for consumers, but also unsafe for consumers due to its omni directional radiation, especially harmful to human brain.
Since the radiation of mobile phones does not draw attention by people, the mobile phone makers have not been developing a unidirectional radiation antenna. In the market nowadays, mobile phones with a hidden antenna are very few, and not to mention a sticker antenna. Besides, there is no unidirectional radiation sticker antenna to replace a common antenna. At present an antenna having an electromagnetic wave absorbing cover can achieve the effect of unidirectional radiation by covering half of the antenna, but this kind of antenna does not completely replace the conventional antenna.
In conclusion, it is desired for consumers to have a convenient unidirectional radiation sticker antenna.
The mobile phone sold in the current market adopts a helical coil antenna which extends from the mobile phone and thus is broken easily. This kind of product not only causes an inconvenience when carrying, but also damages human health due to omni directional radiations from the antenna. In use, the mobile phone is close to the user""s ear, and the antenna is in the proximity of the user""s brain. Strong radiation waves transmit to the user""s brain. It will cause damage to the user""s brain in a long time usage.
Since electromagnetic waves cannot penetrate through metal foils, the circuit board of the mobile phone is equipped with a large metal cover, and all electronic components on the circuit board are covered inside the metal cover to shield external electromagnetic interferences. When people use a mobile phone, the circuit board is at the side of the human brain, and the metal cover is at the other side. If a sticker antenna can be designed and adhered on the housing near the metal cover, the radiation waves from the antenna will propagate in a direction away from the human brain.
The present invention uses the above characteristic to design many kinds of flat sticker antennae, including spiral, square, elongated, curve and logarithm forms, which are adhered on the metal cover of the circuit board of the mobile phone or on the inside or outside of the housing near the metal cover to generate a unidirectional radiation and replace the conventional antenna.
The structure of the sticker antenna is simple, and conductive materials of the antenna in a particular pattern are printed on a soft resin film or hard resin substrate. The resin materials can be selected from normal thermal plastic resin (vinyl series) or tough plastic, such as polyester resin, polyimide resin, etc. The method for manufacturing the sticker antenna includes screen printing, evaporation, sputtering and chemical electroplating, which prints conductive materials such as metal or oxide representing patterns on the resin substrate. Besides, an etching or molding manufacturing method transfers the resin films of the conductive layer on the resin substrate. If the pattern is made from colorless and transparent materials, such as tin and indium oxide or zinc oxide, the pattern cannot be easily found on the surface of the sticker antenna. A lot of color patterns can be printed on the surface of the sticker antenna to enhance the asthetics. A typical thickness of the film is 0.075 to 0.125 mm and the thickness of the pattern will not be over 0.1 mm. Therefore, the total thickness of the antenna will not be over 0.25 mm. For example, the weight of a 40 mmxc3x9740 mm sticker antenna will not be over 0.4 g, which is almost one twelfth of the traditional helical antenna. If the housing of the mobile phone is designed in a double layer form, the sticker antenna can hide between the two layers, or directly printed on the inner side of the housing.
It is not necessary to install a conductive wire to electrically connect the sticker antenna and the circuit board, and the antenna and circuit board can interact by electromagnetic induction. If the sticker antenna is installed outside the housing, the only thing to do is to adhere the sticker antenna on the housing. A user can remove the original helical antenna, and install a small conductive rod on the antenna slot where the original antenna situated. If the sticker antenna is installed inside the housing, the only thing to do is to adhere the sticker antenna on the radiation-shielding metal cover or on the inner side of the housing. If an antenna slot on the circuit board touches the sticker antenna, the small conductive rod can be omitted. The conductive rod on the antenna slot works as a part of the antenna, and leads electromagnetic waves from the circuit board to the sticker antenna. Therefore, the conductive rod functions as an induction rod. In well receiving region, the conductive rod is not needed. The conductive rod can in a form of screw, and for reducing weight, the material of hollow aluminum can be adopted, no matter it is solid or hollow. After the induction is inserted, the hold due to the removal of the original antenna can be filled with a rubber plug to enhance beauty of sense. If the induction rod has a big head, it can fill the hole completely and no rubber plug is needed.